Power for a He-Ne laser is provided by a special high voltage power supply and consists of two parts (these maximum values depend on tube size – a typical 1 to 10 mW tube is assumed): Operating voltage of 1,000 to 3,000v DC at 3 to 8mA.Like most low current
Time for another teardown! I managed to fish this Sky+ box out of a skip, but to protect the guilty, all serial numbers have been removed. These are pretty smart devices, with DVR capability on board. There’s a lot of ports on these units, from RS-232 serial, POTS modem, eSATA,
Here is an AVR powered optical tachometer design, that I adapted from the schematic found here. I made a couple of changes to the circuit & designed a PCB & power supply module to be built in. The original design specified a surface mount IR LED/Photodiode pair, however my adjustment